The genetic transmission of eye tracking abnormalities will be studied. Also, the P50 auditory evoked potential (an EEG abnormality), phenotypes abnormal to schizophrenics, and about 50% of the unaffected relatives will be studied. These phenotypes will be used to determine a quantitative liability to schizophrenia, which will be used as a sensitive phenotype to search for predisposing gene(s) for schizophrenia. Linkage and linkage disequilibrium will be employed using data from: 1) moderately sized Utah pediagrees; 2) a fully ascertained sample form the island population of Palau, Micronesia, and 3) schizophrenics and their first degree relatives form the isolated inbred populations of Dahestan, Russia. This is a "core lab only" protocol.